DL-Phenylalanine and vitiligo

What 2 graded rows on dl-phenylalanine agree on for vitiligo, and where they differ. Counted side by side, never averaged.

Consensus finder Rows from the DL-Phenylalanine page, reviewed Oct 21, 2026 How it decides

What the rows agree on

Each block and row is one graded row from the DL-Phenylalanine page, with its PubMed record.

Supplement

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2 rows · 45 people

They agree: both rows found an improvement.

No difference

Improved

Each block is one evidence row, sized by how many people it enrolled, with its grade inside.

From the rows

The best-graded row, grade D, is a randomized trial of 32 people (1994) and found an improvement.

The rows run from 13 to 32 people, published from 1989 to 1994: 2 single studies.

2 improved

Grade DSkin repigmentation in vitiligo with UVA light · Improved
RCT · n 32 · 1994 · Patients with vitiligo (Netherlands); a separate open trial enrolled 149
Weight-based; the authors judged the best dose to be under 50 mg/kg/day · 6 months (blinded trial); 18 months (open trial)
Repigmentation was reported in both trials, up to 60% in the blinded trial and 77% in the open trial; higher doses raised blood levels but not results.
Row on the DL-Phenylalanine page · PubMed 8186511 (opens PubMed)
Grade DRepigmentation in childhood vitiligo with UVA light · Improved
Observational · n 13 · 1989 · Children with vitiligo
Not stated in the abstract · Not stated in the abstract
3 children repigmented fully, 6 improved by 50 to 90% and 4 did not respond; no side effects were reported.
Row on the DL-Phenylalanine page · PubMed 2616391 (opens PubMed)